The ALD (Atomic Layer Deposition) process is known as a vapor phase growth method. Japanese Patent Application Laid-Open Publication No. 2010-98141 describes that the ALD process is used to deposit an aluminum oxide (Al2O3) film from materials of TMA (Tri-Methyl-Aluminum, trimethylaluminum) and water (H2O). The ALD process is a method of alternately supplying source gases to deposit monoatomic layers of an insulator layer by layer.